Cracked knuckle?

[Track/S]

Originally Posted by TT1351

What troubles me is that this is a known issue, BMW by proxy has acknowledged this issue by manufacturing an upgraded and hopefully improved version. I think for low mileage non tracked cars (yes there are some) it should be automatic that they honor the replacement. For tracked cars with modifications I also think they should step up to the plate, it's not like this car was created to go to church on Sundays, they brag how well it did at Nürburgring, so the intent to create a track warrior is there. Shame on BMW for talking all this crap about the M Driving Experience, and then turning their back on you when a substandard and apparently poorly designed part fails doing something this car was designed for. Modern cars do everything amazingly well, are crazy fast but what they lack is soul, and it seems BMW lacks heart in standing behind a product intended for the track. If this were a rare occurrence they may have a case. but these have failed on a high percentage of cars. There, I feel better!

BMW rarely took responsibility for their shit, luckily there are ingenious people who try to solve those shits on their own.

Originally Posted by JustAnothaM4

wait...what am I looking at here?

Are you seeing the difference or do you need a sketching?

[JustAnothaM4]

Originally Posted by Prodrive_X

BMW rarely took responsibility for their shit, luckily there are ingenious people who try to solve those shits on their own.

Are you seeing the difference or do you need a sketching?

Nope, i'm not really seeing it. Looks like less material on the updated version and possibly better welding?

[TT1351]

The mounting points at the top of the photos are completely different, revised version is beefier and seems to lack what appears to be openings that conceivably pinch when torqued in place would allow additional clamping force. The outer edges are considerably larger on the superseded piece as opposed to the original part where the inner and outer portion of each lobe appear to be about the same size. I think one of the original photos earlier in the thread was somehow omitted, original post has all the images and offers a better illustration.

[Track/S]

Originally Posted by TT1351

The mounting points at the top of the photos are completely different, revised version is beefier and seems to lack what appears to be openings that conceivably pinch when torqued in place would allow additional clamping force. The outer edges are considerably larger on the superseded piece as opposed to the original part where the inner and outer portion of each lobe appear to be about the same size. I think one of the original photos earlier in the thread was somehow omitted, original post has all the images and offers a better illustration.

They have eliminated the reinforcement of the red circle, and it makes sense, the reinforcement does not allow it to yield when tightening, without the reinforcement the piece has less tension (admits more flex)




The mounting points at the top are the same, I don't see any change in that area.

[SYT_Shadow]

Originally Posted by Prodrive_X

They have eliminated the reinforcement of the red circle, and it makes sense, the reinforcement does not allow it to yield when tightening, without the reinforcement the piece has less tension (admits more flex)




The mounting points at the top are the same, I don't see any change in that area.

Exactly. The extra reinforcement of the original one is just a stress concentration point

[Track/S]

Today I modified a couple:

[SYT_Shadow]

Originally Posted by Prodrive_X

Today I modified a couple:

Fantastic work. When I head to Spain I should bring mine for you to modify!!

[Track/S]

Originally Posted by SYT_Shadow

Fantastic work. When I head to Spain I should bring mine for you to modify!!

I got the photos of the new version:

[JustAnothaM4]

ahhhhhh...I see whats going on here..

[SYT_Shadow]

Both GTS1 and GTS2 are up on lifts now and we've been looking at the differences.
For clarity, GTS1 has the new knuckles and GTS2 has the originals.
I bet the 'v2' knuckle is the 'v1' knuckle with some extra machining to remove the stress concentration spot

Many thanks to Prodrive_X for the idea

Using the v2 knuckles as a template we will transform our originals into the revised model, just like Prodrive did!

[Track/S]

Originally Posted by SYT_Shadow

Both GTS1 and GTS2 are up on lifts now and we've been looking at the differences.
For clarity, GTS1 has the new knuckles and GTS2 has the originals.
I bet the 'v2' knuckle is the 'v1' knuckle with some extra machining to remove the stress concentration spot

Many thanks to Prodrive_X for the idea

Using the v2 knuckles as a template we will transform our originals into the revised model, just like Prodrive did!

Exactly, the only thing they did is change the cnc program eliminating the excess material.

Today i mount the knuckles on my m2c:

[Gomeler]

Turns out my extended factory warranty is still active. It was just voided for my front suspension, yay! The "lowering springs"(AKA OEM GTS KWs..) and camber plates(true, this car should have shipped with these by default) killed my warranty repair claim on my cracked front left knuckle.

Dealership wants ~$5000 to fix the front left, guessing the front right will cost the same. I know I'll break it if I don't get it milled to fix BMWs mistake. But at the end of the day the $10k doesn't really hurt, it's the lack of ownership from BMW on this flawed piece on their halo trackday toy. I'd happily throw $10k at a diff and transmission refresh, or a rotating assembly refresh. Those get me more happy miles. But god damn knuckles? I'm annoyed.

I tracked the car ~1600 miles of ~3600 miles on it. Multiple friends/family drove the car, many people passengered in it, and I took it to several cars and coffee meetups. Fully within BMW's right to void the warranty and deny the repair, but just annoying to know the thing I bought the extended warranty for won't be covered.

Anywho, my wife doesn't understand why I'm annoyed about the stupid toy that our son sits in and yanks levers on, so that's my rant. Escalated the ticket to BMW NA, maybe someone knowledgeable about the F82 GTS will see it and say "ahh yeah, we fucked up there". If not I'll probably fix the front left and toss the car into storage for a good long while. I still love my M235iR, and I can drive that instead.

edit: go out and check your knuckles! I imagine a few cars like mine still have ~1 year of extended warranty left.

[Track/S]

Originally Posted by Gomeler

Turns out my extended factory warranty is still active. It was just voided for my front suspension, yay! The "lowering springs"(AKA OEM GTS KWs..) and camber plates(true, this car should have shipped with these by default) killed my warranty repair claim on my cracked front left knuckle.

Dealership wants ~$5000 to fix the front left, guessing the front right will cost the same. I know I'll break it if I don't get it milled to fix BMWs mistake. But at the end of the day the $10k doesn't really hurt, it's the lack of ownership from BMW on this flawed piece on their halo trackday toy. I'd happily throw $10k at a diff and transmission refresh, or a rotating assembly refresh. Those get me more happy miles. But god damn knuckles? I'm annoyed.

I tracked the car ~1600 miles of ~3600 miles on it. Multiple friends/family drove the car, many people passengered in it, and I took it to several cars and coffee meetups. Fully within BMW's right to void the warranty and deny the repair, but just annoying to know the thing I bought the extended warranty for won't be covered.

Anywho, my wife doesn't understand why I'm annoyed about the stupid toy that our son sits in and yanks levers on, so that's my rant. Escalated the ticket to BMW NA, maybe someone knowledgeable about the F82 GTS will see it and say "ahh yeah, we fucked up there". If not I'll probably fix the front left and toss the car into storage for a good long while. I still love my M235iR, and I can drive that instead.

edit: go out and check your knuckles! I imagine a few cars like mine still have ~1 year of extended warranty left.

You can bought a used one:

Left & right 620euros

[SYT_Shadow]

I've found them new for 2600. But instead I just modified mine, I have to post the pics sometime.

[Gomeler]

Originally Posted by SYT_Shadow

I've found them new for 2600. But instead I just modified mine, I have to post the pics sometime.

Depending on how this goes, I might just buy a new front left, and have my front right milled to the same profile. I assume a competent machine shop can do it. Or, did you just use a milling bit in a drill like Prodrive_X ?

[SYT_Shadow]

Originally Posted by Gomeler

Depending on how this goes, I might just buy a new front left, and have my front right milled to the same profile. I assume a competent machine shop can do it. Or, did you just use a milling bit in a drill like Prodrive_X ?

It wasn't hard. I used an angle grinder and then a dremel to leave it very smooth.

Just send me your knuckle, I'll do it for free. Obviously after a liability waiver, but the work is very straightforward

The most surprising thing about this debacle is it is horribly obvious to anyone who did a single course of materials elasticity and resistance that the v1 design won't work.


We had heard of this topic and never paid attention to it, until prodrive posted the photos and then it's quite obvious.

[Gomeler]

If folks are having success with just hand tools I can grind and polish the front right, no need to ship it. We'll see what BMW NA says about the front left, might need to shop around for a front left 2019 knuckle if it's all denied. Would want a 2019 just so I can replicate the profile, assuming BMW did some modeling to figure out what it should look like on the second attempt.

For sure on Prodrive_X making it painfully obvious how small of a correction is needed, huge thanks for those images showing the difference.

[SYT_Shadow]

Originally Posted by Gomeler

If folks are having success with just hand tools I can grind and polish the front right, no need to ship it. We'll see what BMW NA says about the front left, might need to shop around for a front left 2019 knuckle if it's all denied. Would want a 2019 just so I can replicate the profile, assuming BMW did some modeling to figure out what it should look like on the second attempt.

For sure on Prodrive_X making it painfully obvious how small of a correction is needed, huge thanks for those images showing the difference.

I'll try to post what I did as well. I took a lot of pics as I had GTS1 & 2 to compare

It isn't hard because you're trying to remove extra thick sections that end up in a really thin part, which is where the failure occurs. The v2 ones do not have those thick sections.

[Track/S]

Gomeler
With a drill it would be uncomfortable to work, i use Milwaukee dgl34 grinder with cutting tool for aluminium


SYT_Shadow
Did you remove them from the car? I want to do it on my gts without disassembling them.

[SYT_Shadow]

Originally Posted by Prodrive_X

Gomeler
With a drill it would be uncomfortable to work, i use Milwaukee dgl34 grinder with cutting tool for aluminium


SYT_Shadow
Did you remove them from the car? I want to do it on my gts without disassembling them.

I used an angle grinder with a 'diablo' disk, which worked very well for the blunt work
Then a sanding disk on a dremel to clean it up


I did not remove them from the car. I removed the rotor and turned the wheel all the way one way and then the opposite for the other side. It provides good access, there is not much to be gained by removing it completely

[Track/S]

Originally Posted by SYT_Shadow

I used an angle grinder with a 'diablo' disk, which worked very well for the blunt work
Then a sanding disk on a dremel to clean it up


I did not remove them from the car. I removed the rotor and turned the wheel all the way one way and then the opposite for the other side. It provides good access, there is not much to be gained by removing it completely

I had planned to do that too, this weekend I will do it

[SYT_Shadow]

Many thanks to Prodrive_X
Anyway, GTS1 has the v2 kingpin and GTS2 has the v1. We parked them by each other and that made the process easy. You could do this modification without photos of v2 because all you're trying to do is remove the stress concentration.

The tools are simple: a dremel for fine work and a angle grinder for the big work.
We used a random angle grinder with a 'diablo' disc, the same one we used to modify the M3 Invisihitch into a M4 model that they don't sell.



We used a black sharpie to mark the area we were trying to get rid of




The almost-final result, just needs some polishing


Final result




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